Autostop mechanism



May 12, 1925. y 1.531069 D.YC'DAVIS AUTOTOP MECHANI SM Filed Auz. 29. 1921 INVENTOR Patented May 12, 1925,

UNITED STATES PATENT OFFICE.

DAVID C. DAVIS, OF CHESTER, PENNSYLVANIA, ASSIGNOR TO TESTINGHOUSE ELEC- TRIO ANI) MANUFACTURING COMPANY, A CORPOBATIQN Ol PENNSYLVANIA.

AUTOSTOP MECHANISM.

Application filed August 29, 1921.

To all whom t may concern.'

Be it known that I, DAVID C. Davis, a citizen of the United States, and a resident of Chester, in the county of Delaware and State of Pennsylvania, have invented a new and useful Improvement in Autostop Mechanismof which the following is a specification.

My invention relates to a safety and alarm system for lubricating systems and has for its object to provide apparatus of the character designated which shall effectually warn the operator in case the oil circulation stops in a lubricating system; and it may further serve to stop machinery with which said lubricating machinery is associated, in case the oil circulation fails.

A further object is to'provide a method and apparatus for efl'ectually removing conducting particles, such as metal or carbon, from the oil of a circulating system.

In the accompanying drawing, Figure 1 `is a diagrammatic view of a steam turbine provided with a thrust bearing of the tilting-shoe type and with other appropriate elements, illustrating a preferred form of my invention; Figure 2 is an enlarged View of a portion of the thrust bearing shown in Figure 1, illustrating detailslof my invention; and Figure 3 is a view similar to Figure 2 and illustrating a modification in the structure thereof. v v It is the usual practice to lubricate large heavy-duty bearings such, for example, as the shaft bearings rand thrust bearings of steam turbines, by means of a forced oil circulation and it is essential that this oilV circulation be continuo-us, inasmuch as the operation of the bearings for a very short period of time, in the absence of oil, causes serious injury thereto. In particular', it is necessary that the lubrication of the thrust bearing of a turbine be maintained, inasmuch as the failure of the bearing, upon the cessation of oil flow, frequently permits such cndwise movementof the spindle as to seriously damage the blading.

My invention relates, in its essence, to making use of the insulating property of Ithe ordinary oil film in maintaining an electrical circuit in open condition, the failure `of the oil film, upon the cessation of oil flow, permitting contact between the normally separated bearinvf surfaces, with the ringing of an alarm be l or the blowing of Serial No. 496,546.

a whistle, and, if desired, with the automatic shutting` down of the turbine or other apparatus with which the bearing may be associated.

My invention is of particular adaptability in connectionv with bearings of the Kingsbury or tilting-shoe type in which a wedge-shapcd film of material thickness is at all times maintained between the'bearing` surfaces under normal operation, and in which metallic contact is immediately established upon the failure of the oil supply.

Another feature of my invention is that inasmuch as the oil is constantly passing between spaced conducting surfaces, between which a difference of potential is maintained, a minute arc is established upon the passagel of a conducting particle and said yparticle is destroyed by vaporization, thus tending to maintain the purity of the oil supply.

Referring to the drawing for a more detailed understanding of my invention, I show a turbine at 10, in Figure 1 provided with a steam supply 11, having a throttle valve 12 therein.

The shaft of the turbine 10'is shown at 13, this shaft driving a governor 14, of the usual form, and also carrying a thrust collar 15 adapted to bear against a thrust bearing of the Kingsbury or tilting-shoe' type, as indicated at 16. The shoe 1G is preferably insulated, as shown at 17 in Figures 1 and 2 and, furthermore, is preferably formed with a relatively hard metalbaclting portion 18, as of brass or iron and a soft metal face 19 formed, for example, of Babbitt metal.

A solenoid or other electromotor device 2O is provided for the closure of the valve 1Ql and is in circuit with the shoe 16 and with an electromotive source 21, the other terminal thereof being grounded as at 22 through a switch 23 and the thrust collar 15 being grounded by virtue of its connections to the machine.

A contact point Q4 isl provided adjacent the governor so'as to make contact with a portion thereof when the governor is in iis normal full-speed position, thus automatically establishing a ground connection with the lower terminal of the solenoid 20.

An alarm device 25, together with a switch 26 therefor, is connected in shuntrelation to the device 20 and the device 2O may-be removed from circuit, as by open-v ing a switch 27. ,The solenoid QOis shown as of the sluggish or slow-movingitype, as indicated by a damping winding 28, for a purpose to' be hereinafter more fully explained.

'Having thus described the structure of apparatus constructed :in accordance with my invention, the operation thereof is as follows Upon Yputtingthe turbine into service, the rotation ofthe oil lpump atoncevsupplies oilto the thrust bearing and an oil film is estab-yl lished between thelthrust collar and the. shoe 16,1this -film effectivelyinsulating these-4 two members fromljeach other.` Upon the closureof tlieiswitches 23' and 27, the device is in circuit :with the current'source 21,1 thefcircuit being-'broken only at :the oil film. 7Upon.thefailure of theoil supply or when,

for-any reaso n,. the film is destroyedfthe-V Collar l'malresfcontact with the shoe 16? `device 25 is rung, provided the switch 26.1:

and the circuit` is closed,` energizing the .device 20a1id cutting off the steam supply at' the valve 12 and at `the same time the alarm is closed' The full speedoperation of the turbine ycauses the governor 14 to assume its high speed position, under which circunr stances,` contact is made with thelcontact member 24 and thus i agground is automativplacing the-damping winding-28 on the coil 20, thezcoil is made'sluggish in action-and does not respond tothe current flow 1in these minute arcs so as to cut offt-he steam in response thereto, although the device 20 is valve12 upon y'the establishmentl of a long-V elements 15 and 16.

continued closure of the circuit between the` y Referring; tothe form of my deviceshownf. in Figure"3,'the thrust 'collarl 15 is opposed by the tiltingl shoe '16, having a hardgmeta'l backing-18 and a soft metal face 19, all as. hitherto, ,except that an `opening` .is provided through the shoe at a substantially central portion thereof and-a conducting vvpinBO is vmounted inthisopening` so as to terminate just short ofthe bearing face of the portion 19.V vThe pin 30 is insulated, as at 31and is connected in circuit ias` before, lthrough a Lwire 32. y

During, normal operation, the circuit is notclosed, inasmuch as .the pin 30' does not come into contact with the collar 15, butv upon the failure .of the oilv supply, the `soft metal'face 19 isV rapidly fused and the pin 30 in connectionwith anyftype of machinery ugherewith; bearings Vare employed and Which,l during normal operation, embodyV an oililmof material thickness. lVhile Il have illustratedaibiit one-,tiltingshoe.in .each of .theffbearings shown, it is well understoodin the art that a series of such shoes is. mounted, vfacing 'thethrust-ycollaig and my` invention may Vbeapplied to o ne or` more of such shoeS, as desired.

`While I have shownluy-inventionV invtwo forms, -it vwill beI obviousto those. skilled in the art that it 'is not Iso limited, butis -susceptible of vario-us other changes and modifications without departing .from the spirit thereofand lI ldesire, therefore, that `only such limitations shall bepla'ced thereupon as are imposed bythep'rior. artor as are speccally set forth -n thea appendedv claims.

lVhat l claimis:

1f rlhe combinationwith a bearing structure embodying 11n oilcfihn, of an electric circuit .including a.translatin'g device, and means .depending upon .the insulating l,properties of saidA film for niodifyingl said circuit.' i

The combination with a bearing structure embodyingvan oil lm,-of an electric circuit including a translating device, and

meanswhereby said circuit normallyopen by virtue of the insulating,properties of saidy iilmand .whereby said circuitis closed, upon thefailure of said oil.filin,'for the energization of said .translating device. still operative in full degree. to close theo` tion, awedge-shaped'oil ilin is maintained Abetween the bearing surfaces, of insulating meansfor at least one of 'saidlsurfalceg and an `electric circuit including Aa .translating deviceland .said bearing surfaces, whereby, upon the .failure of said'oil lilith and the consequent contactin'guof the bearing faces, said circuitisclosedV and lSaid traiislatingdevice is 2f energized. l Y 4. The combination` vitl i a' driving device, of a Vbearingr structure' associated therewith and normally,embodying. an oil film, a deenergizing'` device for said driving device, and an electric circuitincluding Vsaid deenergizing device and 'said oil film, whereby, during` normal operation, said circuit is maintained broken by the insulation afford-` ed by said film .and is closed by the failure i of said film for the operationof 'saidde` energizing device and the stoppage of said driving device.

5. The combination with a driving device, of a bearing structure of the tilting-shoe type associated therewith and normally embodying a wedge-shaped oil film of substantial thickness, a cle-energizing device for said driving device, and an electric circuit including said de-energizing device and said 10 oil film, whereby, during normal operation,

said circuit is maintained broken by the insulation afforded by said film and is closed by the failure of said film for the operation of said cle-energizing device and the stoppage of said driving device.

In testimony whereof, I have hereunto subscribed my name this 24th day of August, 1921.

DAVID C. DAVIS. 

